Ideally, in the graphs above, as the analog input increases at a certain rate, the output codes would also increase at the same rate. If the output codes increase at a different rate than the analog input does, this results in gain error. Gain error can be defined strictly as the difference between the level that produces the greatest code and the smallest code, versus the ideal levels that produce these codes. Also, in an ideal situation, the data converter would begin to notice deviations from a true zero voltage. However, because of offset error, a small constant analog voltage is always present before the conversion begins to function linearly. These errors, as seen here in the graphs, are commonly alleviated through signal conditioning.